In industrial buildings and warehouses it is often desired to have a door or closure to separate two areas of the building which are subjected to different ambient conditions, or to separate the inside of the building from the outside. The door should be capable of quickly moving between a closed and open position, so that material handling equipment, such as a fork lift truck, can move through the doorway without delay. Fast movement between the open and closed positions also benefits in minimizing energy losses.
In order for the door to move at high speed it should be lightweight, and yet capable of handling pressure differentials and wind loads, without undue deflection.
As a further requirement, the door should be durable and capable of yielding to impact by material handling equipment so as to prevent damage to the door or to the material handling equipment or to personnel.